Extract find_package calls from CMake build scripts

Add a query that pulls out the find_package calls from CMake build scripts. This will give a package name (or a variable whose value would need to be determined...) that we could then search for a corresponding package in a Linux dataset for something that provides a Find.cmake, Config.cmake, or <lowercase_package_name>-config.cmake file.

If a project follows good practices like allowing users to point the build at an external copy of any vendored libraries, for our symbols data set this could give a way to avoid claiming that functions in a vendored piece of code are part of the project doing the vendoring.

Start by locating the query or analysis entry point that processes CMake build scripts, then trace how dependency names are represented. Define the expected handling for literal and variable-based find_package calls, and check the Linux dataset matching for Find.cmake, Config.cmake, and lowercase package-config files. Done means the query can identify external packages without incorrectly treating vendored code as project code.